Control system.



' F. H. SHEPARD.

CONTROL SYSTEM.

APPLICATION FILED IAN. 6, I9I5` Patented Aug. 14, 1917.

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or NEW ROCHELLE, NEW Yomr,

ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING' COMPANY, A.CORPORATION OF PENNSYLVANIA.

CONTROL SYSTEM.

To all lwhom 'it may concern:

Be it known that I, FBANCIs H. SHEPARD, a citizen of the United States,and a resident of New Rochelle, in the countiof Westchester and State ofNew Yor have 1nvvented a new and useful Improvement in Control Systems,of which the following is a specification.

My invention relates to control systems for dynamo-electric machinesthat are employed for propelling electric locomotives or other electricvehicles, and it has special reference to the control of polyphaseinduction motors that are'governed by means of a plurality ofelectro-pneumatically' operated liquid rheostats. v

One of the objectsv of my invention is to provide a control system catedcharacter by means of which the loads upon the respective driving units,whether they be motor-driven axles, trucks, or half units of an electriclocomotive, may be regulated at the will of the operator, or the totalload of the locomotive may be divided in any proportion between theseveral driving umts, irrespective of variations in the mechanicalconstruction and electrical characteristics of the several drivingmotors and their accessory governing apparatus.

Another object of my invention is to provide a system, of the generalclass referred to, which shall embody relatively few and ineXpens`veauxiliary control devices, the arrangement and circuit connections ofwhich shall be simple, and which shall be adapted, under the control ofan operator, to effect the results hereinbefore mentioned withreliability and` positiveness.

In another aspect, it is an object of my invention to provide a systemof motor controlembodying a plurality of driving units that are governedby electro-pneumatically operated liquid rheostats, and to makeprovision for permitting the operator to concurrently control theoperation of the driving units, and, moreover, to permit of independentcontrol of anyofsaid units.

lVith present day manufacturing methods,

it is practically impossible to commerciallyy construct motors, liquidrheostats and operating mechanisms therefor which shall be identical inconstruction, electrical charac- 'teristics and operating qualities and,therefore, in electrically propelled vehicles and locomotives of thetypes referred to, there is Specification of Letters Patent.

of the above-indi- Fig.

Patented Aug. 14, 1917'.

Application filed January c, 191s. sensi No. 7a4.

usually a tendency for certain of the driving umts to take a greaterportion of the load than is intended. Moreover, diiferences in thediameters of the driving wheels and other mechanical dierencescontribute to inequalities in the division of load between the severaldriving units. It, therefore, becomes necessary to provide means forcorrecting for the inherent diderences in the operation of the variousdriving units.

In my co-pending application, Serial No. 852,7 99, filed July 2li, 1914,I have set forth automatic means for attaining the ends in view.

According to my present invention, however, I propose to accomplish thesame general results, but to do so b means of a simplified system whichis entirely under the control of the operator.

In describing the'circuit connections and operation of the sytem ofcontrol of my invention, I shall, for the sake of simplicity, set fortha system of the multiple-unit type for governing the operation of a pairof polyphase induction motors through the agency of separateelectrically controlled liquid, rheostats, the several motors beingmounted upon the respective driving trucks of a single locomotive unit.It should be understood, however, that the particular location of themotors is unessent-ial, and that my invention is equally applicable tolocomotives having trucks severally provided with a pair of drivingmotors or to a locomotive comprising a pair of half units.

In the accompanying drawing, Figure 1 is a view, in side elevation, of alocomotive having driving motors that may be conveniently controlled bya system of control embodying my invention; Fig. 2 is a diagrammaticview of the main control apparatus and main circuit connections of acontrol system arranged in accordance with my invention; Fig. 3 is adiagrammatic view of the auxiliary control circuits and apparatus forgoverning the operation of the main control devices shown in Fig. 2; and4 is a simplified diagrammatic view of a modified system of controlcircuits and apparatus for governing the operation of a portion of themain circuit devices shown in Fig. 2.

Referring to the drawing, a locomotive 1 comprises a plurality ofdriving trucks 2 and 3 that are severally provided with polyv closingthe discharge opening an phase induction driving motors M1 and M2 and acab 4 that is supported upon the 'trucks 2 and 3.

The motors M1 and M2 embody primary windings P1 and P2 and secondawindings S1 and S2, respectively, the primary windings being adapted toreceive energy from a plurality of supply-circuit conductors 5, 6 and 7through a plurality of line switches A1, B1 and C1 and A2, B2 and C2.

rality of liquid rheostats LRl and LR2.

The rheostats LRl and LR2 are of like construction, although theirspecific structural details form no material part of my presentinvention, and each embodies a tank 12 having a bottom discharge opening13 in which a combined discharge and regu1ating valve 14 is disposed forthe urpose of d) for regulating the level of the electrolyte which iscontinuously supplied to the rheostat through. an inletv opening 15.

The several discharge and regulating valves 14 lare tubular in form and4are respectively -mechanically associated with electrically governedoperating mechanisms CM1 and CM2. Since the contruction and operation ofthese mechanisms are similar, only oneof them will be described. Themechanism CM1 comprises a cylinder 20, a movable piston 21 containedtherein, and a plurality of electrically operated valves off-1 and on-1that are adapted to govern the admission and release of operating fluidto and from the cylinder 20.- The valve oils- 1, when denergized, isadapted to admit operating fluid from av source (not shown) to the upperend of cylinder 2O and to prevent any communication with the atmosphere,while the valve 0n-1, when deenergized, cuts oli'` the supply ofoperating fluid to the lower end` of the cylinder 20 and .establishesa'communication to the atmosphere. Under these conditionsLoperatingiluid is admitted above the piston 21 and exhausted beneath it, and,hence, said piston and its associated valve 14 are biased to theirlowest positions in which the discharge opening 13 is partially openedto permitl the escape of the 'continuously supplied electrolyte.

Reference may now be had to Fig. 3 in which is shown a master controllerMC comprising a movable conducting segment 25 and a plurality ofstationary contact terminals B+, LS{, on-2, on-1, of-1 and ol"-2 whichare adapted for coperative engagement upon the position-indicating lineslower, hold and raise, for the purpose of concurrently governing theoperation of the mechanisms CM1 and CM2.

In addition, a plurality of rheostat switches RSl and RS2 are providedthat are respectively adapted to mdependently control the. operation -ofthe mechanisms CM1 and CM2 of the respective rheostats LR1 and LR2. Therheostat switch RSl comprises a plurality of movable conducting segments26 and 27 that are adapted to cooperatively engage a plurality ofstationary contact terminals 28,129, 30 and 31 upon theposition-indicating lines raise, off and lower. The rheostat switch R82is of similar construction and 4embodies movable conducting segments 33and 34 and a plurality of stationary contact terminals 35, 36 37 and 38.y

ln setting forth the operation of the system and in tracing the circuitsthereof, only the main elements of the system will be recited, and theenumeration of the various electrical conductors will be omitted for thesake of clearness, it being believed that a clear understanding of theinvention may be obtained without the necessity of completely tracingall of the circuit connections.

The master controller MC is first movedl into its position raise inwhich a circuit is completed from the positive terminal of a battery B,or other suitable source of energy, which includes contact terminal B+and conducting segment 25 where the circuit divides, one branchincluding terminal on-2, terminal 37, conducting segment 34, terminal38, and thence through the energizing coil of the magnet valve on-2 tothe negative terminal of the battery B; another branch includes terminalon-1, terminals 30 and 31-that are bridged by the conductingsegment 27ofthe rheostat switch BS1-4 and thence through energizing coil of themagnet valve on-1 to the battery; another branch is completed throughterminal ol"-1 and terminals 28 and 29-which are bridged by theconducting segment 26 of the rheostat switch RS1, Aand thence throughthe energizing coil of valve olf-1 to the battery; and still anotherbranch includes terminal oil"2, terminal 36, conducting segment 33,terminal 35 and energizing coil of magnet valve off- 2 to the bat teg.

aving completed the circuits all of the ma offf2 and on- 2 are energizedand actuated into their opposite posit1ons whereby the operating fluidcontained within the upper ends of both 'cylinders 20 is released, whilea supply of operating l'luid is admitted beneath the pistons 21. Theunbalanced just recited,

et valves off-1, on-1,

pressure conditions thusy effected cause the pistons 21, and hence therespective chargeJ and regulating valves 14, to be raised in pos1tion,thereby closing the severalds charge openings 13 and permitting the;inflowing electrolyte to rise in bot rheostats LR1 and LR2'to spondingtothe upper ends of said valves.;

stats LRl and LR2 becomes gradually raised,'the resistance in thesecondary circuits of the motors M1' and M2 is reduced, and, hence,

the motors and their actuating mechanisms are identical, the load isproportionately divided between them. However, such conditions arerarely secured with commercial ap aratus and, for purposes ofexplanation, 1t will, therefore, be assumed that by reason of certaindifferences, the spec' c nature -of which is immaterial, the motor M1has a to carrymore than its intelzul'edthe load, as will be indicatedthe motorman or operator by the compara"-l tendency share of tiveindications of the devices I, and I2.

In order to re-distribute the load uponthe motors M1 and M2, theo eratormanipulates the rheostat switch R. 2 by moving it into its lowerposition. Thus, the circuit f of the magnet valve off-42 -is interruptedby the disengagement of contact terminal 35 with the conducting segment33, while;-

thatof valve magnet ou-2. is maintained by reason of the engagement ofcontact terminals 37 and' 38 with the conducting segs which bridges saidterminals.4

mentv 433, Y Thus, the valve Oife-2 is denergized to admit operatingduid above the piston 21 fof the operating mechanism CM2, while thesupply of operating fiuid'beneath said piston is maintained by reason ofthe continuous energization of the valve on-e2. Balanced pressures,therefore, act upon the piston 21 of the mecha "Sm CM2 and, therefore,urther movements of said piston and` its associated regulating `valve 14arev prevented.

The level of the electrolyte within the rheostat LR2, thereoreis` heldconstant, whilev that in the rheostat LRl continues to rise, whereby themotor M1 gradually increases its load and the motorA M2 operates underconstant load conditions until the desired balance of load is obtained,as shown by the indicating means I1 and lf2, As soon,

as the desired load conditions are secured,

therheostat switch RS2 is moved bacia to its od position andsubsequently, the regulating valves 14 of both rheostats LRl and ILR2are again raised concurrently to eilect the acceleration of both motorsM1 and M2. Obviously, if it is found that the motor M1 is taking morethan its share of the load,

.of lthey rheostat balanced-loadsare securedwhen the rheooi' the' alevel -correv Y "iStats LRl and '-LB2` is resumed. `By reason As theelectrolyte level within the rheo-y 'ageny of a switch RSl these motorsare corr espondi'ngly' accelerated in speed.v Obviously, ,thevv total;

load is carried by -motors M1 `and M25 and in the event thattheoperating characteristics of f moved to its lower rtherheostat switchRSl may be moved to its position marked Lower, whereby movement of thevalve 14 further upward LRl is discontinued until statswitch. R51' isreturned to its olf position, and concurrent operation of the rheolofthe simplicity and` similarityofthe circuit connections establishedthrough `the to` those hereinbeore traced in connection with themanipulavtion of switch KS2, it is deemed unneceary to describe thecircuits and operation.

'upper [ends vof the Ycylinders 20, thereby eifecting a balance ofpressures actin upon the movable pistons 21 and arresting, urthermovements thereof,...

lf, under these conditions, the indicating meansA is overloaded, therheostat switch RS2 is position, whereby the disengagement of contactterminals 37 and 38 from the bridging contact member 34 is effected,thus, vinterrupting the energizin circuit of the coil lci" magnet valveon- 2. The 'valve on- 2 therefore returns to its initial position topermit the escape of operating Huid, whence, the unbalanced Xpressuresacting upon the piston 21 cause said piston and its valve 14 to beforced downwardly to lower the level of the electrolyte within therheostat LR2 and, hence, 'to 'reduce the load upon the motor M2.

, without further description, it `wi11 be' understood that, in lieu ofdecreasin the load upon the motor M2, a balance of l(loads may besecured by causing the motor M1 to carry a larger portion thereof bymoving'the rheostat switch RSl to its raise position 'and therebyenergizing the-coil of magnet valve off-1 to effect unbalanced pressureconditions that act upon the piston 21 of the I1 and I, show that themotor M2 tion, thereby also effecting the disengagement of stationarycontact terminals on-1 and on--2 from the conducting segment 25. In thisposition, all of the magnet valves on-1, on-2, off- 1 and off-2 aredenergized, and the unbalanced pressures within the cylinders 20 aresuch as to effect the simultaneous downward movements of the respectivepistons 21 and regulating valves 14. The electrolyte levels wlthin therheostats LRl and LR2 are thus concurrently lowered and,hence, the speedand load of both motors M1 and M2 are decreased.

In the event that one of the motors becomes overloaded during thisoperation, the operator may establish balanced load conditions betweenthem by suitable manipulation of the one or the other of the rheostatswitches RSI and RS2, as will be understood.v

From the foregoing description, it is evident that the operation of theseveral mechanisms OMl and OM2,and,hence,of the respective motors M1 andM2 may be governed concurrently by the operator through the agency ofthe master control MC, while the rheostat switches RS-l and RS2 permitof independent control of either motor in order to correct forunbalanced load conditions.

Reference may now be had to Fig. 4, which discloses an auxiliarv controlsystem ofa modified type for permitting the independent control of eachof the several magnet valves off-1, on-4, of-2, on-2 by means ofseparate manually operated switches marked Raise- 1, Lower-1,7 Lower-2and Raise-.2, which may conveniently takev the form of push-buttondevices.

Each of the switches just referred to comprises a set 40 of stationarycontact terminals and a plurality of movable conducting segments thatare mounted upon a movable carrier 42 and are adapted for coperativeengagement with the set of terminals 40 upon the position-indicatinglines down and up. The carrier 42 isprovided with an actuating member orpush-'button 43 and is maintained in its up position by means of aspring 44.

The push-button switch raise-1 comprises stationary contact terminals50, 51 and52 and movable conducting segments 5.3 and 54; the switchlower-1? comprises stationary contact terminals 55, 56, 57, 58 and 59and movable conducting segments 60, 61, and 62; the switch lower-2embodies stationary terminals 63, 64, 65, 66 and 67 and conductingsegments 68, 69 and 70; and the switch raise-2 is provided withstationary terminals 70, 71 and 72 and conducting segments 73 and 74.

If the apparatus and circuit connections be assumed to occupy thepositions shown, in

the operation of the system is as are, bridged by' conducting segment 61of the switch lower*l and energizing coil of valve on- 1 to conductor B.Another circuit is established from conducting segment 25a throughterminal off and thence through a divided circuit, one branch of whichincludes terminals 7l and 72 and conducting segment 73 of switchraise-2, terminals 66 and 67 and conducting segment 69 of switch lower*2and energizing coil of magnet valve off-2 to conductor B`-, and anotherbranch including terminals 51 and 52 and conducting segment 54 of switchraise-1 and terminals 55 and 56 and conducting segment 60 of switchlower-1 and energizing coil of magnet valve oif*1 to the B- conductor.

Upon the completion of the circuits just recited, all of themagnetvalves off-1, on-l, off-2 and on- 2 are energized and actuated, whenceunbalanced pressures are eii'ected within the several operatingcylinders 20 that serve to raise the respective' pistons 2l and theirassociated regllfting valves 14 of the rheostats LRl and Under theseconditions, the motors M1 and M2 are started into operation and areconcurrently brought up to speed. If, for any reason whatsoever,'themotor M2 has a tendency to carry a greater portion of the load as s ownby the indicating devices I1 and I2, the switch lower-2 is actuated toits down position, thus breaking the circuit Aof the energizing coil ofthe valve of-2 by the disengagement of the conducting segment 69 fromthe terminals 66 and 67, while maintaining a circuit through the coillof valve on-2 by means of terminals 64 and 65 which are bridged by theconducting segment 70 in the down position of said switch. Upon thedenergization of valve off-2, it is permitted to return to its initialposition to admit operating fluid to the upper end of the associatedcylinder and to arrest further movements of the piston 21 and regulatingvalvel 14 of rheostat LR2. Inasmuch as the operating mechanism OMlcontinues to raise its associated valve 14, the motor M1 aduallyincreases its load until the desired division l thereof is obtained, asshown by the indi- The switch lowcating means I1 and I2.

er-2 is then released and permitted to return to its up position toreestablish its initial circuit connections through the coils of thevalves on- 2 and olf-2. The concurrent operation of the mechanisms OMland CM2, therefore, is resumed.

In case the load upon the motor M1 becomes excessive, it is within thepower of the operator to reestablish balanced load conditions merely byactuatin switch lower-1 and thereby den'ergizing the coil of magnetvalve off-1 while maintaining the energization of magnet coil on-1 in amanner similar to that just described. Thus, further upward movements ofthe operating mechanism vOMI are prevented,4 thereby permitting themotor means to ei'ect 'of both rheostats M2 to assume a greater portionof the load until the desired division of load is secured, whence, theswitch lower-1 is released and i concurrent operation resumed.

No further detail description of the circuit connections yand operationof the system will be given, it being deemed sulcient merely to statethat concurrent operation LRl and LRQ may be secured by moving themaster controller to any of its operative positions raise, hold andlower, while independent control of the operation of any of the magnetvalves C oH-l 77 L( on 1, C 77 and 44,0!12 35 may be effected bysuitable manipulations of the respective switches raise- 1, lower-1,lower-2 and raise-2.

Although I have shown and described my invention as embodying laspecific arrangement of circuit connections and apparatus and mode ofoperation, it will be understood that my'invention is not restricted inany way to that which is hereinbefore set forth, and may be embodied ina system having materially different connections and structural featureswithout departing from the spirit and scope of my invention. I desire,therefore, that only such limitations shall bey imposed as are indicatedin the appended claims.

I claim-as my invention:

1. The combination with a plurality of resistance-varying devices, andmeans for severally actuating said devices to vary the resistance valueof the governed circuits, of means for concurrently controlling theoperation of said actuating means, and means for independently governingthe operation thereof.

2. The combination with a plurality of iiuid-pressure-actuated devicesand electromagnetic means for severally governing the operation thereof,of electr1cal remote-control means lfor concurrently controlling theoperation of said electro-magnetic governing corresponding movements ofsaid fluid-pressure devices, and other electrical remote-control meansfor independently controlling the operation of .any of saidelectro-magnetic governing means whereby non-corresponding movements ofsaid fluidpressure devices are efected.

3. The combination with a plurality of liquid rheostats, and means forseverally actuating said rheostats to iX the level of the electrolytetherein, of means Jfor concurrently controllingthe operation of saidactuating means, and means for severally and independently governing theoperation thereof.

4. The combination with a plurality of liquid rheostats, and means forseverally regulating the levels of the electrolyte therein, of commonmeans for concurrently controlling the actuation of said regulatingmeans, and a plurality of independent means severally adapted to controlthe actuation of the'respective regulatin means.

5. The combination witli a plurality of liquid rheostats, and means for.severally regulating the levels of the electrolyte therein, of commonelectrical means for edecting concurrent movements of the respectiveregulating means, and a plurality of auxiliary control means in circuitwith saidcommon control means for severally and independently governingthe movements of the respective regulating means. v

6. In a control system, the combination with a plurality of liquidrheostats and uid-pressure-actuated means associated with each rheostatfor regulatingthe level ci the electrolyte therein, of means forconcurrently controlling the operation of said duid-pressure means, andmeans for independently governing the operation vof the respectivefluid-pressure means.

7. In a control system, the combination with a plurality of liquidrheostats and luidpressure-actuated means associated with each.-rheostat for regulating the level of the electrolyte therein, ofelectromagnetic means for governing the operation of said fluid-pressuremeans, remote-control means for concurrently governing 'the operation ofsaid electro-magnetic means to ellect correspending movements of saidduid-actuated means, and auxiliary remote-control means forindependently governing the operation lll) current operation of theseveral fluid-presmeans for severally controlling the operation of saidfluid-pressure means.

9. In a system of control,1the combination with a plurality of liquidrheostats severally having movable valves for regulating the level ofthe electrol te therein, and electrically controlled Hui-pressure meansfor severally actuating said valves, of electrical means for effectingconcurrent o erations of said fluid-pressure means, an switching meansin circuit with said electrical means for effecting independentoperations of said fluid-pressure means.

10. In a system of control, the combination with a pluralit of li uidrheostats severally associated t erewit and havin movable valves forregulating the level o the electrolyte therein, and electricallycontrolled means 'for raising and 'lowerin said valves for governing theload upon t e respective rheostats, of remote-control electrical meansfor concurrently governing the operation of said electrically controlledmeans, and a plurality of independently operated means for separatelycontrolling the operation of said electrically controlled means andcausing either of said valves to be raised, lowered or held at rest atthe will of the operator.

11. The combination with a plurality of liquid rheostats severallyhaving movable valves for regulating the level of the electrolytetherein, fluid-pressure devices respectively adapted to actuate saidmovable valves, and a plurality of electrically controlled valvesassociated with each of said devices, of a master controller and circuitconnections for concurrently governing said valves to cause thefluid-pressure devices to effect corresponding movements of theirassociated regulating valves, and a plurality of auxiliary switchesseverally in circuit with the valves of the respective Huid-pressuredevices for independently governing the operation of the respectiverheostats.

12. The combination with a plurality of liquid rheostats severallyhaving movable valves for regulating the level of the electrolytetherein, fluid-pressure devices respectively adapted to actuate saidmovable valves, and a plurality of electrically controlled valvesassociated with each of said devices, of a master controller forgovernin the energization of all of said electrica ly controlled valvesand for effecting consure devices, and a plurality of auxiliary switchesseverally adapted to independently govern the energization of differentvalves.

13. The combination with a plurality of liquid rheostats severallyv.having movable valves for regulating the level of the electrol tetherein, fluid-pressure devices respective y adapted to actuate saidmovable plurality of electric motors, a

valves and a plurality of electrically controlled valves associated witheach of said devices, of remote-control means embodying a master switchfor concurrentl governing the energization of corresponding,electrically controlled valves of each rheostat and a plurality ofswitching devices for severally governing the energization of both ofthe valves associated with the respective fluid-pressure devices, saidswitchin devices being severally interlocked with t e energizingcircuits of both valves to be governed.

14. I n a stem of control, the combination with a plurality of electricmotors, power-actuated resistance-varying means for governing theoperation thereof, and means embodying a master controller and circuitconnections for concurrently electing the operation of all saidresistance-varying means, and a plurality of auxiliary master switchescoperatin with certain of said circuit connections or independentlyeffecting the operation of said resistance-varying means and modifyingthe load conditions upon the respective motors.

l5. In a, system of control, the combination with a pluralit of liquidrheostats severallyhaving mova le valves for regulating ,the level ofthe electrol therein, and electricall controlled flui -pressure meansfor severa y actuating said valves, of a master switch and circuitconnections for eifecting multiple control ofthe respective iluidressuremeans, and a plura ity of auxi iary switches associated with differentcircuit connections for independently modifying the operation of thefluid-pressure means.

16. In a system of control, the combination with a plurality of liquidrheostats severally having movable valves for regulating the level ofthe electrolyte therein, and electrically controlled fluid-pressuremeans for severally actuating-said valves, of a master switch andcircult connections for concurrently governing the operation of saidHuid-pressure means, and a lurality of auxiliary switches in circuitwitg certain of said circuit connections for severally and independentlychangin the circuit connections of the respective uid-pressure means,whereby the operation of any of said fluidpressure means may be modiliedat will.

17. In a system of control, the combination with a plurality of electricmotors, of a plurality of resistance-varying devices associatedtherewith, means for concurrently governing the operation of saiddevices, and means forl independentlycontrolling the re- 'spectivedevices to effect changes in the distribution of load between themotors.

18. In a system of control, the combinaplurality of electric'motors, ofa tion with a plurality of variable translating devices as- Sociatedtherewith, .iuid-perated actuating In testimony whereof, I have hereuntosubscribed my name this 29th day of December, 1914.

FRANCIS H. SHEPARD. Witnesses:

WM. H. CAPEL, C. WESLEY POMEROY.

